diff --git a/glymur/test/test_printing.py b/glymur/test/test_printing.py
index 8b7ba34..7680377 100644
--- a/glymur/test/test_printing.py
+++ b/glymur/test/test_printing.py
@@ -689,6 +689,7 @@ class TestPrinting(unittest.TestCase):
 
                 # Now append the codestream.
                 tfile2.write(codestream)
+                tfile2.flush()
 
                 jasoc = glymur.Jp2k(tfile2.name)
                 print(jasoc.box[3])